Week 4 - Sources of Variation

Natural

Errors in DNA replication

Errors in cell division

Mutations

Natural selection

Meiosis

Induced

Mutagens

Cloning

Chromosonal Mutations

Deletion

Inversion

Duplication

Nondisjunction

Translocation

Recombination

Translocation vs Recombination

Non homologous vs homologous (crossing over)

3 Changes to Chromosome Number

Monoploidy - 1 copy

Polyploidy - extra set

Aneuploidy - add/lose

Aneuploidy - Trisomy Examples

Down - 21

Patau - 13

Klinefelter - XXY

Aneuploidy - Monosomy Example

Turners - X0

Conserved Region

Important part of DNA that has stayed unchanged throughout evolution

Point Mutations - Conserved Region

Deleterious

Point Mutation - Coding Region

Missense - change amino acids + protein

Nonsense - short/disfunctional protein

Silent - no change

Point Mutation - Non Coding Region

RNA processing/stability

Splicing

Point Mutation - Regulatory Region

Too much/little protein

Point Mutation - Intergenic Region

Little/no effect

Transition Mutation

Base replaced by same type

AG

CT

Transversion Mutation

Base replaced by diff type

4 Effects of Point Mutations in Coding Regions

Missense

Nonsense

Silent

Frameshift

2 Effects of Point Mutations in Non Coding Regions

RNA splicing

RNA cleavage

RNA Splicing Errors

Introns not removed

Wrong mRNA

Wrong protein

RNA Cleavage Errors

Wrong cut in pre-mRNA before adding poly a tail

Unstable mRNA

Regulatory Regions - 3 Types

Promoter

Enhancer

Silencer